Broaching apparatus



April 19, 1938. E. A. BAUMBACH 2,114,276

BROACHING APPARATUS I Filed Nov. 2, 1935 3 Sheets-Sheet l fz, HI j? E. A. BAUMBACH 2,114,276

BROACHING APPARATUS Filed Nov. 2, 1935 3 Sheets-Sheet 2 April 19, 1938.

Apri] 19, 1938. E, BAUMBACH 2,114,276

BROACHING APPARATUS Filed Nom-2, 1955 s sheets-sheet :s

5 tion.

Patented Apr. 19, 1938 UNITED STATES PATENT oFicE BROACHING APPARATUS Emil A. Baumbach, Chicago, Ill.

Application November 2, 1935, Serial No. 47,936 4 claims. (ci. rio-s) My invention relates to broaching apparatus. One of the objects of my invention is to provide improved broaching apparatus which will insure greater accuracy in the broaching opera- A further object is to provide an improved broaching apparatus which will prevent the broaching tool from drifting laterally, causing the axis of th-e hole to be slanting or off center.

A further object is to provide an improved broaching apparatus which will enable a relatively heavy cut to be made, thus lessening the number of cutting edges required and enabling the use of a shorter tool.

`-` Further objects and advantages of the invention will appear from the description and claims.

In the drawings, in which my invention is illustrated,

Figure 1 is a perspective view of my improved broaching apparatus;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a section on the line 3-3 of Fig. 1;

Fig. 4 is a fragmentary, front, elevational View showing the broaching tool in position in the apparatus;

Fig. 5 is a section on the line 5 5 of Fig. 4; and

Fig. 6 is a sectional View similar to Fig. 5 but showing the use of the broaching tool for making a rectangular hole.

Referring to the drawings in detail, vthe construction shown comprises a broaching tool I (Fig. 4) having upper and lower chuck-engaging portions 2 and 3 and a series of longitudinallyspaced cutter edges 4 on its intermediate portion, a work-supporting table 5 for supporting the work 6 being operated on, two aligned breach-engaging chucks 'I and 8, one above and one below the table, reciprocable longitudinally in unison to guide the broaching tool in its movement and to support both ends thereof against longitudinal movement, chuck-supporting slides 9 and l0 on which the chucks are mounted, guide means II and I2 for guiding the slides, power means I3 for effecting up-and-down movement of the upper chuck-supporting slide, power means I4 for effecting upward movement of the lower chuckcarrying slide to bring it into engagement with the lower end of the broach, manual means I5 for effecting the final adjustment of the lower chuck to the broach, clutch means I6 for controlling the drive from the motor I'l to the lower chuck-carrying slide I0, controlled in its clutchengaging movement by a-pedal I8 and controlled automatically in its clutch-disengaging move- 'ment by the upward movement of the lower chuck-carrying slide I0, and brake means I9 for opposing the requisite resistance to the downward movement of the lower chuck-carrying slide II).

Before describing the construction in further detail, I will briefly outline the operation.

The guide means I I and I2 for the chuck slides are carefully adjusted to bring them into alignment and with their axes precisely perpendicular to the plane of the work table 5. The work 6, here shown as a die shoe having a hole .'l to be broached to the proper diameter, is placed in position on the smooth work table. The broaching tool I is dropped into the hole 2l) from above and allowed to move downwardly in the hole as far as it will go. The lower chuck slide I is then caused to move upwardly by pressing down on the pedal I3 to operate the clutch I6 to cause the motor I'I to move the lower clutch slide I0 upwardly. The pedal I8 is held depressed until it is lifted by the upward movement of the lower chuck slide to disconnect the clutch I6. The automatic clutch-shifting apparatus 2i is so set that it will disengage the clutch when the lower chuck is brought approximately into engagement with the lower end of the broaching tool. The final adjustment of the lower chuck 8 to the broaching tool I is effected byv manually adjusting the hand wheel 22. The upper chuck slide 8 is then caused to move downwardly by depressing the pedal 23 to bring the upper chuck 'l into engagement with the upper end of the broaching tool and then to force the broaching tool through the hole in the work, In this broaching operation, the work can thus adjust itself easily to the position of the broach by shifting to a properly centered position on the work tabl-e 5.

Referring now more in detail to the construction, the guide means II for the upper chuck slide 9 is adjustable, both fore and aft, and .I

laterally, as shown more particularly in Figs. 1 and 3, The guide construction comprises a channeled guideway 2d in which the slide 9 operates and upper and lower pairs of adjustable brackets ,25 for carrying this channeled guideway. The

channeled guideway is secured to the upper and lower pairs of brackets by means of studs 26 firmly secured to the guideway 24 and mounted for limited sliding movement in openings in the brackets 25. A slight lateral adjustment of the guideway may be effected by turning the adjusting screws 2l' which are threaded in the brackets 25 and the ends of which engage the side edges of the guideway 24. After the guideway has been properly adjusted laterally, it is secured in this adjusted position by means of set screws 23 threaded in the brackets 25 and engaging the slidable studs 25. The fore and aft adjustment of the guideway is effected by the provision of slots 2Q in the brackets 25 through which extend cap screws 33 threaded into the frame of the apparatus. Adjusting screws 3| are provided for eifecting an accurate fore and aft adjustment of these brackets, mounted in lugs 32 secured to the sides ofthe frame and having their ends engaging the brackets. The slide 9 is held in place in the guideway by means of retaining strips 33 secured to the guideway by means of screws 34. Suitable adjustable gibs 35 are provided for taking up wear. By means of this construction, it will be seen that the guideway for the upper chuck slide may be readily and accurately adjusted both fore and aft, and laterally.

The guide means for the lower chuck slide comprise a pair of guide strips 36 engaging slide flanges 37 on the slide and secured to the frame of the machine by means of cap screws 38 extending through slots 39 in the guide strips and threaded into the frame of the apparatus. This construction enables a limited lateral adjustment of the guide strips |2 by means of the adjusting and setting screws 4|! which engage the side edges of the guide strips.

The guide means are also mounted for swinging adjustment about a horizontal transverse axis at 43a (Fig. l) adjacent the lower end of a swinging frame leb which carries the guide strips l2. This swinging frame may be adjusted and held in adjusted position by means of two pairs of screws 45C (Fig. 2), one pair on each side of the main frame, one of each pair of screws being swiveled in the main frame and threaded in the swinging frame, and the other screw of each pair being threaded in the main frame and having its point bearing on the swinging frame. By proper adjustment and setting of these screws 49e, the swinging frame 40h may be brought into a position in which the line of movement ofthe v lower chuck 3 will be exactly perpendicular to the plane of the table 5.

The transmission from the motor to the lower chuck slide Il) comprises a pulley 4| on the motor shaft, a belt 42 running over this pulley, a pulley 43 driven by this belt, a shaft 44 on which this pulley is mounted, a worm 45 on this shaft, a worm wheel 45 driven by the worm 45, the clutch I for controlling the driving connection between the worm wheel 46 and cross shaft 4?, and a pinion 48 on this cross shaft meshing with a rack 49 on the chuck slide Ill. The clutch I5 is moved into clutching engagement by depressing the pedal I8 mounted on the rock shaft 50 which controls the clutch-shifting movement. The mechanism 2| for effecting the automatic disengagement of the clutch i5 comprises a lug 5| secured to the side of the chuck slide I0, an upright rod 52 loosely and slidably mounted in an opening through this lug 5| and having an adjustable abutment 53 on its upper end engaged by the lifting lug 5| as the chuck slide I0 moves upwardly, and a pedal-lifting lever 54 pivotally mounted at 55 and having its forward end extending through an opening in the framework underneath the pedal l5. The lifter rod 52 is connected with the pedal-lifting lever 54 in such manner that when the lug 5| on the chuck slide |0 lifts the rod, the rod will cause the outer end of the pedal-lifting lever 54 to move upwardly to effect the disengagement of the clutch. The abutment 53 on the upper end of the lifter'rod ,.struction, such as a brake shoe 55a. engageable with a brake lining inside the brake drum 56 which is rotatable with the shaft 41. The brake shoe 55a isconnected with the pedal 23 which controls the upper chuck slide. When the operator vhas pressed down on this pedal to start the downward movement of the upper chuck slide, he can impose any resistance he desires to the downward movement of the lower chuck slide I0 by exerting more or less pressure on the-pedal 23. In addition to this foot-controlled shoe brake,

I an additional one-way brake 51 may be provided which will oppose resistance to the downward:

movement of the lower chuck slide but will not interfere with its upward movement. The purpose of this brake is mainly to hold the lower chuck slide in the position to which it may have v been adjusted to prevent itfrom moving downl' wardly under its own weight.

vIn order to limit the extreme downward movement of the lower chuck slide, aknee or abutment 58 is provided, secured to the mainframe of the machine and having a stop portion59 lo cated in the path of movement of the chuck slide to stop it in its extreme lower-position.

In the broaching operation, it will be seen that the breaching tool is supported atboth ends so that it cannot drift laterally to-cause the axis of the hole to be slanting or olf center. yBecause of the fact thatl the broaching tool issupported at both ends, a relatively heavy cut may be made, thus lessening the number of cutting'edges required and enabling the use of a short tool.

Further modifications will beY apparent to those skilled in the art and it is desired, therefore, that the invention be-limited only by the prior art and the scope of the appended claims.

Having thus described my invention, what It.

claim and desire to secure by Letters Patent is:

1. Push `broaching apparatus comprising a work-supporting table,` two `aligned tool-engaging chucks on opposite sides of said table; power means for actuating one of said chucks to pushithe tool through the work to eifectv the broaching operation and causing the tool in its movement to push the other chuck-ahead of it,the chuck being pushed having `provisions for yieldingly resisting the pushing action of the tool to',

maintain this chuck in contact with the tool throughout the work stroke, manually controlled means for movingthe resisting chuck toward the driving chuck to bring the end 'of-the tool adjacent the -driving chuck, and means for stopping.,

the movement of said vresisting chuck when the end of the tool is adjacent the driving chuck.

2. Push broaching apparatus comprising a work-supporting table, ytwo aligned tool-engaging chucks on opposite `sides of said table, power;

ychuck being pushed having provisions.for.yieldingly resisting the pushing action of the tool to maintain this chuck in contact with the tool throughout the work stroke, manually operable means for moving the resisting chuck toward the driving chuck to bring the end of the tool adjacent the driving chuck, means for stopping the movement of said resisting chuck when the end oi the tool is adjacent the driving chuck, and manually operable means for moving the resisting chuck toward the driving chuck to effect the final adjustment of the tool to the driving chuck.

3. Push hroaching apparatus comprising a work-supporting table, two aligned tool-engaging chucks on opposite sides of the table, powen means for moving one of said chucks toward said table throughout the working stroke to push the tool through the Work to effect the breaching operation, means for moving said other chuck toward the table to effect chucking engagement with the tool prior to the Working stroke, and yielding means for resisting throughout the working stroke the movement away from the table of said other chuck to maintain said other chuck in engagement with the tool throughout the Working stroke, said power means having power suicient to overcome said yielding resistance throughout the working stroke.

4. Push broaching apparatus comprising a work-supporting table, two aligned tool-engaging chucks on opposite sides of the table, power means for moving one of said chucks toward said table throughout the working stroke to push the. tool through the work to eiect the broaching operation, means for moving said other chucktoward the table to eiect chucking engagement with the tool prior to the working stroke, and yielding means for resisting throughout the working stroke the movement away from the table of said other chuck to maintain said other chuck in engagement With the tool throughout the Working stroke, said power means having power suflicient to overcome said yielding resistance throughout the Working stroke, said yielding means comprising a brake drum driven from said other chuck and a brake shoe cooperating with said drum.

EMIL A. BAUMBACH. 

